diff

To get coloured diff, install colordiff (http://colordiff.sourceforge.net/) and then you can make some aliases like below:

alias svndiff="svn diff --diff-cmd=colordiff"
alias diff="colordiff -u"

Note that I didn't need the -u (unified diff) option for subversion because it does it by default.

If you pipe your diff through less, the output will be all screwed up, this can easily be fixed by using less -r. I aliased it like this:

alias less="less -r"